With increasing awareness of environmental issues, environmentally-friendly polymers using biomass-derived materials have been developed actively in recent years.
As an example of the development an environmentally-friendly polymer using 1,5-pentanediamine produced from biomass-derived material as a monomer component, addition of a flame retardant to polypentamethylene adipamide (hereinafter referred to as nylon 56) resin is disclosed in JP 2011-52034 A. Further, JP 2011-202103 A discloses that a polyamide having lower water absorption, and higher heat resistance, toughness, and moldability than those of conventional polyamides can be obtained by producing the polyamide using 1,5-pentanediamine with a low content of amino group-containing six-membered ring compounds, which are by-products of raw material preparation.
Japanese Patent No. 2911607 discloses a method regarding a polyamide which is light stabilized and heat stabilized by adding a triacetonediamine compound to a polyamide such as nylon 6, nylon 66, nylon 46, or nylon 610.
JP 2009-531505 W discloses a method of stabilizing a polymer by adding a hindered amine-based heat stabilizer having a piperidine structure to a polyamide such as poly-2,4,4-trimethylhexamethylene terephthalamide, poly-m-phenylene isophthal-amide, polyamide 66, polyamide 46, polyamide 610, polyamide 69, polyamide 612, polyamide 46, or polyamide 1212.
Polyamide resins containing 1,5-pentanediamine, in particular, polyamide resins using 1,5-pentanediamine produced from biomass-derived material as a monomer component tend to cause coloration upon heating, and in the prior art, a polymer satisfactory in color tone of a polyamide resin composition containing 1,5-pentanediamine could not be obtained.
In other words, the polyamide resins using 1,5-pentanediamine as described in JP 2011-52034 A and JP 2011-202103 A have a problem in that they tend to cause coloration upon heating, and a polyamide with excellent whiteness such as polyhexamethylene adipamide (hereinafter referred to as nylon 66) or polycapramide (hereinafter referred to as nylon 6) widely used at present as a general-purpose nylon may not be provided. Further, Japanese Patent No. 2911607 and JP 2009-531505 W are silent about the above-described problem of coloration specific to polyamide resins using 1,5-pentanediamine and a solution thereto.
Thus, it could be helpful to provide a polyamide resin composition with excellent color tone comprising a polyamide resin containing 1,5-pentanediamine and a heat stabilizer.